MSFS has a community folder and supports mods so yes there is nothing wrong with using them. However there are a couple of areas Asobo consider their baby that they are not going to open up for devs, notably weather even if a couple of mods can loosely simulate thermals they are limited and will always be unable to interact with the sim’s own weather which will when finished include the real thing and also default scenery. ATC may yet prove to be another area but obviously not in it’s current state and who knows what else? We are seriously talking about ten years in development with the Metaverse as it’s end product so if anyone doesn’t like this idea of continuous change and updates then there are alternatives.
I will just add that right now they are working on core functionality but there will come a time when they say “Well that’s that done, now let’s go and fix the Isle of Man”.